In the manufacturing of shaped articles, for example by compression moulding of moulding compounds containing curing resins, some excess material is pressed out between the mould parts in the form of a burr. This burr must be removed from the article after its release from the mould and the edges of the article must be finished by trimming and perhaps polishing. This finishing often requires considerable handwork. In order to avoid this, finishing apparatus has recently been introduced in which the article is placed on a rotating disc whereafter the articles are brought into contact with a tool. This contacting has however involved many problems.
In some cases the rotating disc is mounted in a fixed position while the treating tools are movably mounted for contact with the article. Since tool and motor are usually built into one single unit for practical reasons, this arrangement means that a very heavy weight must be moved to and pressed against the article, which involves problems in providing strong enough holding means for the tool unit to avoid vibrations, problems, in the adaption to different article shapes and sizes, problems in moving the tool unit quickly into contact with the article, and problems in regulating a slight pressure between the article and the heavy tool unit.
In other cases the tool is mounted in a fixed position while the rotary article holder is movably mounted and brought into contact with the tool by means of a spring pressure. In these cases problems have arisen both with the arrangement of the driving means for the rotating article holder, which arrangement tends to be complicated, and with the spring pressure characteristics, which give rise to bouncing and vibrating effects between tool and article and an irregular treating result.
For these reasons hitherto used finishing apparatus have in general been usable only for articles of simple shape, e.g. plain dishes, and have not been usable for articles of more complicated shape.